Gentlemen,
I just changed the muffler on my ‘69 Charger 12.
There are quite a few Gravely 18543 aftermarket mufflers out there so I decided to purchase 2; 1 from Amazon for $45 and 1 from NAPA (7-03679) for $72. Both are made in Taiwan and while the Amazon muffler actually felt a tad heavier to me, its welded construction was poorer so I decided to use the NAPA muffler.
To complete the installation, I needed a 1.25” x 4” black pipe nipple and a 5/16” x 1-1/4” exhaust clamp (NAPA 733-5323).
In conclusion, it seems to me the sound out of the Gravely style muffler is noticeably quieter than the classic pepper pot. Worth the $80 to me!
Link to my YouTube video: